The latest Fedora development snapshot makes Ext4 the default file system and adds experimental support for the next generation btrfs filesystem. "According to current plans, version 11 of Fedora, which is expected to arrive in late May, will use Ext4 as its standard file system. That's what the Fedora Engineering Steering Committee (FESCo) recently decided, following a heated discussion in an IRC meeting. If however Ext3's successor encounters big problems with the pre-release versions of Fedora 11, the developers will dump that plan and revert to Ext3."

Although it'll undoubtedly increase the testing and improve the adoption rate and the driver itself, I can't not to notice it's typical for FOSS projects to quickly embrace fresh and yet unproved technologies. That's just how it works here, but it might leave a bad taste for some unsuspecting users.

I wish the best luck for ext4 project and a painless migration for all of us

'Fresh and unproven technologies', mate, it is a natural evolution of EXTFS, it is hardly an 'unproven technology'. Its no more 'unproven' than when Microsoft updates NTFS to offer more features/enable features that weren't available in the previous Windows generation.

EXT4FS is hardly what one could deem a 'revolutionary' leap forward, it is a conservative movement forward that isn't disruptive by any stretch of the imagination - and the changes made aren't exactly so risky that it makes it 'unproven'.

Using the same benchmark then maybe we should call all of Microsoft's file system drivers so far as 'fresh and unproven' given they suddenly appear or features suddenly added to NTFS without a 'adequate testing period' (what ever that means).